Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.

This is generally a hardware issue - if the computer is under warranty get it fixed through Acer. If not you may need professional help. You don't mention how old the laptop is but if it is older than a year or two and you live in a dusty environment it could be overheating. If the fan is not running or always running on super-high then it is probably overheating.

Another thing to try is using a boot CD (any boot CD will work) and see if the computer still shuts down after that 30 seconds. If yes, definitely hardware. If not, possible that it's a windows issue.

is this happening everytime you start the machine? What is being displayed on the screen? Do you hear the fans running when you press the power button? Do you hear the disc drive running? Do you hear the cd drive click once and the light on the cd drive door come on for a second or two? Is it posting anything on the screen during the boot process? Is it getting to the actual windows desktop which is where you see your icons? Computers shut down for a reason. Either some piece of hardware is not working such as a fan, or some hardware is faulty (such as the memory, cpu or motherboard), or some software issue or a virus has taken over.

In fact for a full month when I first boot the computer, the fans runs,
no extra beeps, the light blinked correctly but no bios at the screeen. I
remarked also that the fans run full speed doing a lot of noise. Then I
stopped the computer and wait 2 minutes and then it always works
correclty at the second boot with the bios screen appearing. Also, the
fan calm down after 1 second with less noise. So when I start the
computer and hear that the fan calm down with less noise after 1 second,
I know that the computer will boot correctly. That happens always at
the second try after waiting 2 minutes. But since yesterday, the fans
never calm down and the noise still remains high with no Bios at the
screen. I'm suspecting the Power Supply...

Contact GATEWAY, and get them to fix your laptop.
The fan is designed to run at "full-speed" when you first turn it on, and then there are temperature sensors that slow the fan down, to minimize noise, while the computer is "cool" enough that the fan does not need to run. The sensor is malfunctioning, and is not turning-on (or turning-up) the fan when the computer gets "warm".

if you have 2 memory sticks, (i.e. 2 ram sticks that are 2 gb each) try putting on in and start it. if it does not work try this.
remove all power supplies (cord and battery).
hold down the power button for 30-60 sec.
after that plug the power in and try turning it on.

Hello their again if the problem is in your Power Plug i strongly suggest you to change it with new one than to repair with not sure.
for the reason it will be caused an addtional problem that may occur to your Laptop.

Could be this is a driver error on boot up, when it starts to boot up keep pressing F8, this will bring up the safe mode menu, look for the line and highlight 'Last Known Good Configuration' and press Enter.
If this works all is well, but if not press F8 again o boot up but this time highlight the line 'Start Windows in Safe Mode'.
If the laptop then boots up in safe mode without shutting down, run your anti virus and spyware programmes.
If non found and the laptop still has'nt crashed, then it's a driver problem (as not all the drivers load up in safe mode) and you will need to try a system restore to before the problem started.